Transactions are defined using a Forth-like scripting language.[7]:ch. 5 Transactions consist of one or more inputs and one or more outputs. When a user sends bitcoins, the user designates each address and the amount of bitcoin being sent to that address in an output. To prevent double spending, each input must refer to a previous unspent output in the blockchain.[82] The use of multiple inputs corresponds to the use of multiple coins in a cash transaction. Since transactions can have multiple outputs, users can send bitcoins to multiple recipients in one transaction. As in a cash transaction, the sum of inputs (coins used to pay) can exceed the intended sum of payments. In such a case, an additional output is used, returning the change back to the payer.[82] Any input satoshis not accounted for in the transaction outputs become the transaction fee.[82]
Чтобы вернуть украденные средства, было предложено сделать откат сети путем хардфорка. Это позволило бы сделать бэкап блокчейна в начальное состояние – еще до кражи с The DAO. Полного консенсуса в сети добиться не удалось, поэтому параллельно с Ethereum появился Ethereum Classic – версия «до отката». Несмотря на то, что хардфорк позволил вернуть украденные инвестиции, его подвергли критике, так как был нарушен один из главных принципов работы блокчейн – необратимость операций.

Bitcoin, along with other cryptocurrencies, has been described as an economic bubble by at least eight Nobel Memorial Prize in Economic Sciences laureates, including Robert Shiller,[145] Joseph Stiglitz,[204] and Richard Thaler.[205][206] Noted Keynesian economist Paul Krugman has described bitcoin as "a bubble wrapped in techno-mysticism inside a cocoon of libertarian ideology",[136] professor Nouriel Roubini of New York University has called bitcoin the "mother of all bubbles",[207] and University of Chicago economist James Heckman has compared it to the 17th-century tulip mania.[206] Former Federal Reserve Chairman Alan Greenspan has also described bitcoin as a "bubble";[208] the investors Warren Buffett and George Soros have respectively characterized it as a "mirage"[209] and a "bubble";[210] while the business executives Jack Ma and Jamie Dimon have called it a "bubble"[211] and a "fraud",[212] respectively.

Является ли Bitcoin еще запрещен в Индии